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NATURE 



{Dec. 5, 1878 



can easily conceive that other causes may be acting in the 

 formation of species, causes of which we have no idea at pre- 

 sent. To decide what importance natural selection has in 

 the origin of species is left to the judgment of the various 

 naturalists, and in this question the authorities differ materially 

 even to-day. Some ascribe a greater, others a smaller im- 

 portance to it. But the different estimation of the value of 

 Darwinism is quite independent of the absolute validity of the 

 theory of descent, because the latter is up to the present the only 

 theory which explains, in a rational way, the origin of species. 

 If we abandon this theory then nothing remains but the irra- 

 tional supposition of a miracle, of a supernatural 'creation.' 

 We will briefly designate this mystical belief in a creation as 

 ' creatism.' In this decisive and inexorable alternative Virchow 

 has now publicly stated his belief in creatism and his disbelief in 

 transformism." The author then dwells at some length on 

 this, and quotes from the Zeitschrift fiir Ethnologic, edited 

 by Virchow and Prof. Bastian, in which the lattter applauds 

 Virchow's Munich address, and ridicules Haeckel's "deliramenta 

 and absurdities." There is no doubt, therefore, that Virchow 

 has confessed himself a "dualist and creatist," and is as con- 

 vinced of the truth of his principles as Haeckel is of the con- 

 trary as a " monist and transformist," yet the former still refrains 

 from acknowledging his principles in all their consequences. 

 " On the contrary he still clothes his opposition in the favourite 

 phrase of the clerical papers, viz., that the theory of descent is an 

 ' unproved hypothesis.' It is perfectly clear, however, that 

 this theory will never be ' proved ' if the proofs in existence 

 today are not considered sufficient. How often has it been 

 repeated that the scientific certainty of the theory of descent is not 

 based upon this or that single experience, but upon the totality of 

 biological phenomena, upon the Causal-nexus of evolution ? What 

 are we to think, therefore, of the new proofs for the theory of 

 descent which Virchow demands? " 



In Chapter II. Haeckel undertakes to give some "certain 

 proofs of the theory of descent." He shows that all general 

 phenomena of morphology and physiology, of chorology and 

 ©ecology, of ontogeny and palaeontology, can only be explained 

 by the theory of descent, and reduced to mechanical causes. The 

 guarantee of the truth of the theory lies particularly in the fact 

 that the last simple causes are the same for all these complicated 

 phenomena, and that other mechanical causes cannot be 

 imagined. " Where are we, therefore, to find still further 

 proofs for the truth of the theory of descent ? Neither Virchow 

 nor any other of the clerical antagonists or dualistic philosophers 

 show us where we possibly might have to look for further 

 proofs. Where in the world are we to find 'facts' which 

 speak louder than the facts of comparative morphology and 

 physiology, the facts of rudimentary organs and of embryonal 

 development, than the facts of palaeontology and of the geogra- 

 phical distribution of organisms — in short, than all the known 

 facts from the most various biological domains ? " If proofs by 

 actual experiments are demanded, these proofs have also been 

 furnished by the domestication of animals and plants, and their 

 variations under such domestication. All working naturalists 

 are perfectly well aware to-day that the morphological value of 

 the word "species " is not an absolute but a relative one; nor 

 has it any physiological value. Haeckel points out here that 

 the class of animals which furnish the best "certain proof" 

 that the conception of species has only a relative value, are 

 the sponges : ' ' their liquid form wavers to and fro with extra- 

 ordinary uncertainty and variability, and makes all distinction 

 of species quite illusory." The species question, one of the 

 principal points in the theory of descent, is not even mentioned 

 by Virchow, and Haeckel considers this highly characteristic. 

 He arrives at the conclusion that Virchow has never thoroughly 

 digested the evolution theory, and has never attentively studied 

 Darwin's principal work on the Origin of Species, nor any other 

 work by this author. The remainder of this chapter is de- 

 voted to an account of Virchow's activity, first at Wiirzburg, 

 and afterwards at Berlin. Virchow left Wiirzbiu-g for Berlin in 

 1 856 ; it was at the former university that he made the celebrated 

 application of the cell-theory to pathology, which caused quite a 

 revolution in the latter science. Haeckel considers that the 

 exchange of the narrow sphere for the wider one was not bene- 

 ficial in its consequences, and that the Virchow of the present 

 day has completely changed from the Virchow of 1848- 1856; he 

 points out that only those who are aware of the enormous 

 progress morphology has made during the last twenty years, 

 and have followed this science in all its details, can estimate the 



full value of the theory of descent, and of Darwin's theory of 

 selection. "Whoever wishes to convince himself of what an 

 enormous revolution was caused by these theories, in comparative 

 anatomy particularly, let him compare the classical ' Grundziige 

 der vergleichenden Anatomie ' of Carl Gegenbaur (1870) and his 

 'Grundriss' (1878) with the older books on this science. Of 

 all the colossal progress of morphology Virchow has no idea, 

 since he was ever a stranger to this domain. His great reforms 

 in pathology lie in the domain of physiology, and particularly in 

 that of cellular physiology. But during the last twenty years 

 these two principal branches of biological research have separated 

 more and more. The great Johannes MUller was the last biologist 

 who could comprise the entire domain of organic natural research^ 

 and who acquired immortal merit in both branches alike. After 

 Miiller's death (1858) the two halves fell apart. Physiology, as 

 the special science of the functions of organisms, turned more 

 and more towards the exact and experimental method. Morpho- 

 logfy> on the other hand, as the science of the shapes and forms 

 of animals and plants, could of course make but little use of 

 this method ; it was bound to have recourse to the evolution 

 theory, and thus became essentially a historical natural science. 

 It was just upon this historical and genetic method of morpho- 

 logy, in contrast with the exact and experimental method of 

 physiology, that I laid a particular stress in my Munich address. 

 If Virchow, in his cotmter address, had really refuted the latter 

 in its various details, instead of fighting it with phrases and 

 denunciations, this contrast of principles would at least have 

 been worth minute examination. Yet I do not wish to reproacb 

 Virchow with this, since he is completely involved in the one- 

 sided views of the school-physiology of the present day, and 

 because morphology lies far too widely apart from his domain, 

 to make it possible for him to judge its methods and ends for 

 himself. If, nevertheless, upon every occasion he pronounces a 

 depreciatory judgment upon it, then we must question his com- 

 petence in doing this. It is true that in his Munich speech he 

 prints with large type the phrase, ' That which adorns me is 

 the knowledge of my ignorance.' But I regret' that I must deny 

 him this adornment most completely. Virchow does not know 

 how ignorant he is of morphology. Otherwise he would not 

 have pronounced those crushing sentences regarding it ; he 

 would not constantly designate the theory of descent as 'a 

 hobby,' or 'dreaming," or a? personal speculation, which 

 now inflates itself on many domains of natural science.' 

 Indeed Virchow honours me too much if he calls that my 

 ' personal hobby ' which for more than a decade has become 

 the most valuable common property of morphological science. 

 If Virchow w^ere not so unacquainted with morphological lite- 

 ratvure he would know that it is already completely impregnated 

 with the principle of descent ; that in all morphological work 

 which is carried on systematically and with a certain end in 

 view, the theory of descent is now accepted as quite indispen- 

 sable. But he is unaware of all this, and thus we understand 

 why he continues to ask for ' certain proofs ' for that theory 

 when these proofs have in reality been furnished long ago." 



Chapter III. treats of craniology as applied to' the theory of the 

 descent of man from the ape. Haeckel points out the im- 

 portance of comparative and genetic craniology, but cannot help 

 regretting that a great deal of time and labour has been wasted 

 during the last ten years by ' ' craniologists " with discussions as 

 to the best method of measuring skulls, and also that numerous 

 naturalists, Virchow among others, seem to have seen in " crani- 

 ometry" the highest aim and object of craniological science, and 

 to have forgotten what they really want to prove with their 

 measurements. Turning to the question of the descent of man, 

 the author remarks that the well-known phrase " man hais 

 descended from the ape," which is so often misunderstood and 

 misapplied, can in the sense of the evolution theory but have 

 this meaning : The human race as a whole has descended from 

 the order of apes, i.e., from one (or perhaps more) species of 

 apes now long extinct ; the latest ones in the long series of man's 

 vertebrate ancestors were apes or ape-like animals. Of course none 

 of the species of apes now existing can be regarded as the unchanged 

 descendant of the old parental form. Virchow in his address ex- 

 presses his doubt of the truth of the descent in question, while 

 Haeckel looks upon it as one of the most certain phylogenetic hypo- 

 theses. He does not deny that the relative certainty of this as well 

 as that of any other phylogenetic hypothesis cannot be compared to 

 the absolute certainty of the theory of descent, and draws special 

 attention to the great difference between the whole theory and 

 any particular hypothesis relating to an individual order or class 



